1836660096domain: NAppears in sequencesa(n) = 3*a(n-1) if n is odd, otherwise 6*a(n-1).at n=15A130505Expansion of (1-3*x)/(1-6*x+18*x^2).at n=15A193410Numbers k such that the Diophantine equation x^3 + y^3 + z^3 = k has nontrivial primitive parametric solutions.at n=18A338932